12. Circuit Explanation
1. Principle integrated circuits
A1. HTN19R12 color TV set composed of the following sections
(1) Small signal processing: super monolithic integrated circuits N204(
LA76814A
).
and memory N901 (AT24C08).
(2) Sound power amplifying: integrated circuits N701 (
LA4525
).
(3) Horizontal and Vertical scan output circuits: Vertical output integrated circuits
N402 (
LA78040
), Horizontal output transistor V411 (TT2140), Horizontal flying
back transformer T402 (JF0501-19810).
(4)
Switch power supply: switch transformer T501 (BCK-01-90II), power transistor
V503 (2SD4460).
A2. Main integrated circuits:
(1)
LA76814A
Microprocessor
Picture IF/sound IF/video processing/H and V
Scan/color decoding
(2)
LA78040
Vertical output integrated circuits
(3)
LA4525
Sound power amplifying integrated circuits
A3. Electrical circuit analysis
1
、
Microprocessor and Small signal processing: super monolithic integrated circuits
:
LA76814A
LA76814A
is super large integrated circuit decoder, containing intermediate image
amplifying, intermediate sound amplifying, horizontal and vertical scan, small
signal processing, color decoding, hi-pressure tracing and over-load protection,
I
2
C bus control.
Information introducing functions and testing data for maintenance is listed in Table 1.
1. N701 LC863424B
PIN
Leads Function
Voltage (V)
PIN
Leads Function
Voltage (V)
1
Auto adjust Enable Pin
5.1
19
OSD red signal output
0.09
2
Blank
20
OSD greem signal output
0.09
3
IIC data
4.6
21
OSD blue signal output
0.09
4
IIC clock
4.5
22
OSD blank signal output
0.01
Circuit Explanation
Содержание HTN19R12
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